\documentclass{book}
\usepackage{tikz}
\usetikzlibrary{tikzmark, calc}
\usepackage{array}
\usepackage{multirow}
\setlength{\extrarowheight}{2pt}

\begin{document}
\begin{tabular}{|c|c|c|}
	\hline
	foo & bar                                                             & baz                                                   \\
	\hline
	\multicolumn{2}{|c|}{\tikzmark{smc}\hfill double\hfill\tikzmark{emc}} & B                                                     \\
	\hline
	C   & D                                                               & \tikzmark{smr}\multirow{2}{*}{$\delta$}\tikzmark{smr} \\
	E   & F                                                               &                                                       \\
	\hline
\end{tabular}
\begin{tikzpicture}[overlay,remember picture]
	\draw ($(pic cs:smc)-(\tabcolsep,3.6pt)$) -- ($(pic cs:emc)+(\tabcolsep,10.4pt)$);
	\draw ($(pic cs:smr)-(16pt,17.6pt)$) -- ($(pic cs:emr)+(-3.7pt,2.2pt)$);
\end{tikzpicture}
\end{document}

enter image description here
